People who seek to rise to high office in chronically corrupt states typically go one way or another. They turn corrupt themselves, or they become goody-two-shoes. When you come from a place like that, there can be no middle ground. And very often the ones who manage to stay clean become public officials of notable integrity. So searing is their early exposure to the temptations of influence-peddling that they often turn into even more zealous champions of ethical government than officials from other, less corrupt places. Louisiana, for example—historically a state that's at least as corrupt as Illinois—has long alternated between putting reprobates and good-government crusaders into high office. The current governor, Republican Bobby Jindal, campaigned on a pledge to clean up Louisiana's politics and banish incompetence, and he won handily. (Jindal's two immediate predecessors, Kathleen Blanco and Mike Foster, managed to avoid most allegations of cronyism, but a third, former four-term Gov. Edwin Edwards, remains in federal prison after being convicted of bribery and extortion.)

Now we have cause to question how another product of a chronically corrupt state, Barack Obama, might perform in office. In the aftermath of the arrest of Illinois Gov. Rod Blagojevich on a range of charges, including trying to sell Obama's Senate seat, and questions about whether other prominent Chicago politicians such as Rep. Jesse Jackson Jr. were involved, some in the national media have begun re-examining the president-elect's ethics. Tony Rezko, for one, is back in our sights. The fact that the political fixer was a big-time crony of Blagojevich's and raised funds for Obama—despite the total lack of evidence that he ever received patronage for it—is disturbing enough. While Obama supported ethics reforms as a state senator, he still "has an ambiguous reputation among those trying to clean up Illinois politics," John Fund wrote in the Wall Street Journal on Thursday. Fund went on to quote Jay Stewart, executive director of the Chicago Better Government Association, as saying: "We have a sick political culture, and that's the environment Barack Obama came from ... Obama has been noticeably silent on the issue of corruption here in his home state including, at this point, mostly Democratic politicians."

I may not be right about this, but I suspect that these inquisitive minds have Obama entirely wrong. It was no accident that U.S. Attorney Patrick Fitzgerald went out of his way to say Obama was not implicated in any way. One of the more telling excerpts from Blagojevich's wiretapped conversations indicates the governor was "bleeping" upset that the Obama team was "not willing to give him anything but appreciation" in exchange for appointing the president-elect's preferred candidate, Valerie Jarrett. There's a pattern here. From all the available evidence we can gather from his time in Illinois politics, Barack Obama is a major goody-two-shoes. And that may tell us a lot about what kind of president he's going to be.

The early experience of Harry Truman, one of our greatest presidents, provides some telling clues as to how Obama might perform in office. Though he was, like Obama, a devoted family man, Truman was no angel. "Give 'em Hell Harry" loved bourbon and poker, and when he first arrived in Washington, he was snubbed and derided as the "senator from Pendergast"—as in Tom Pendergast, the boisterous, unapologetically corrupt political boss of Missouri who had made Truman's career. "I was under a cloud," Truman later admitted. George W. Norris of Nebraska, considered the great voice of reform in the Senate at the time, thought Truman was "poison" and refused even to speak to him, as David McCullough wrote in his best-selling 1992 biography.

What few in the Washington bubble (yes, it was a bubble back then, too) understood was that Truman had actually made his career by refusing to engage in Pendergast's patronage politics, to the everlasting annoyance of the old man. Not long after he anointed Truman a county judge, Pendergast was appalled to learn that Truman actually intended to keep his campaign promises "to conduct the county's affairs as economically and efficiently as possible" and "see that every man does a full day's work for his pay," as the candidate put it in a speech. To the outrage of local Kansas City bankers, Truman set about negotiating lower-interest loans with banks in Chicago and St. Louis. Truman also insisted on pushing through a major bond issue to build badly needed roads and to see that they were constructed honestly and well. "The Boss wanted me to give a lot of crooked contractors the inside and I couldn't," Truman later wrote. To the astonishment of all—including the Missouri newspapers—Truman was as good as his word. "It is now generally recognized that every promise made at that time … has been carefully fulfilled," the Independence Examiner reported, five years after the road system was built.

Truman was a man of unimpeachable integrity. But he also realized early in his career that, in the sordid world of Missouri politics, he would need to be, like Caesar's wife, free of any suspicion. Truman made such a point of publicly establishing his independence from the Pendergast taint that when one of his new roads cut 11 acres from his own mother's farm, Truman "felt he must deny her the usual reimbursement from the county, as a matter of principle, given his position," McCullough writes. With her son as presiding judge, Martha Truman never got the $1,000 per acre to which she was entitled. Eventually Pendergast began to develop a grudging admiration for the doughty former haberdasher. "He's the contrariest cuss in Missouri," he said. Pendergast also came to realize that Truman's now-established reputation for incorruptibility could actually be an electoral asset, and he put him up for the U.S. Senate. It was no surprise that Truman later made his national reputation—and brought himself to FDR's attention in 1940—by chairing a Senate commission that exposed widespread profiteering in defense contracting. The rest, of course, is history. And pretty good history at that.